This invention relates to gimballed sighting devices such as periscopes, which may be used in tanks, submarines, or similar equipment provided with an optical sighting system which is normally rotatable at least in azimuth about a vertical gimbal axis and may also include a rotatable elevation mirror.
In previous devices of this type the optic axis of the optical system has been required to coincide with the mechanical axis of the azimuth gimbal in order to avoid rotation of the image. This places severe constraints upon the mechanical design and packaging of the system and on the means by which its gimbals can be provided.
It is an object of the present invention to provide such a device which permits the gimbal axis to be located parallel to and half way between two parallel optical paths so as not to interfere with either optical path and which still is able to relay the image to a fixed position optical sighting system without producing a rotation of the image as the gimballed objective is rotated.